In Guardian interview, Marc Benioff calls out Twitters Jack Dorsey and others for failing to give back to city where they got rich

Marc Benioff, the Salesforce CEO, has escalated his attacks on fellow San Francisco billionaires, saying they are hoarding money and dont want to help the homeless.

In an interview with the Guardian on Tuesday, the tech entrepreneur intensified his criticisms of Jack Dorsey, the CEO of Twitter, saying: He just doesnt want to give, thats all. And he hasnt given anything of consequence in the city.

The growth of tech firms such as Salesforce, a cloud computing company and one of the largest employers in the city, has contributed to a massive housing shortage, with thousands left homeless, including one in 25 public school children. Prop C, which Benioff is backing, is expected to raise between $250m and $300m a year to pay for housing, shelters, mental health treatment and more.

Dorsey, who also runs Square, a second major San Francisco-based tech firm, recently announced his opposition to the measure, saying he did not believe it was the best way to fix the homeless problem.

Benioff said by phone that he had expected Dorsey to stand against Prop C and that he did not anticipate the Twitter co-founder would change his mind or give back in a meaningful way. Thats not a surprise to me. Theres lots of CEOs and companies and billionaires in that category. We have 70 billionaires in San Francisco [Bay Area region]. Not all of them are giving money away. A lot of them are just hoarding it. Theyre keeping it. Thats just who they are and how they look at their money.

He continued: This is a critical moment where I think Prop C kind of illuminates who is willing to be a San Franciscan and actually support our local services.

Benioff also criticized Stripe, a payment platform and another major San Francisco tech firm opposing Prop C. The company claimed the measure lacked a comprehensive plan for spending in a recent op-ed and has also given more than $400,000 to a campaign fighting the measure, making it the largest donor.

Benioff scoffed at the funding from Stripe, which was founded in 2010 by brothers Patrick and John Collison, and was recently valued at $20bn.

Its the most money theyve ever given to anything in San Francisco, so thats exciting [Prop C] will be a direct tax on Stripe that they dont want to have to pay, he said. Even though theyve made $20bn dollars in San Francisco, theyre not willing to give back at scale. Isnt that amazing?

Patrick Collison, Stripes CEO, did not respond to a request for comment on Tuesday. Ted Ladd, a spokesman, said that Stripe earlier this year gave a larger donation to California Yimby, a political group with tech funding that advocates for the construction of more housing in the state.

His decision to be outspoken on Prop C has earned him some praise from progressive activists, especially since the citys mayor, London Breed, recently announced her opposition. The Democratic mayor expressed concern about the flight of headquarter companies and jobs if Prop C passed, a claim that put her in an awkward position after Benioff became a vocal supporter of the measure.

She wants me to fund personally a homeless shelter in the city, because shes out of cash, he said. Thats evidence we need more money now.

He said it appeared that the mayor had decided Prop C is just a risk she cant take.

The mayors spokeswoman did not respond to questions about the reported $8m request, but sent a statement from Breed, saying: I do not believe doubling what we spend on homelessness without new accountability, when we dont even spend what we have now efficiently, is good government.

Benioff said over the years he has learned that there are two kinds of wealthy San Franciscans people who are willing to give and people who are not willing to give, adding: When it comes to this Proposition C, its the same two buckets. Youre either for the homeless or youre for yourself.